This invention relates to gas turbine engines, and specifically to igniter assemblies used to provide ignition in combustors of land-based gas turbine engines.
Land based gas turbines typically have externally mounted igniter assemblies. Due to the high temperature, high stress environment in which such assemblies must operate, such ignition assemblies may experience thermal cracking within the igniter tip causing the tip to withdraw from the combustion liner. Also, movement of the tip within its mounting base can result in poor sealing, thereby permitting combustor air to escape through the mounting base of the igniter assembly. Such conditions are detrimental to the igniter assembly, and may cause the igniter assembly to malfunction, or fail.
What is needed is an igniter assembly that is able to tolerate relative movement between the liner and the case without significantly stressing the electrode, thereby improving the reliability of the igniter.
It is an object of this invention to provide an igniter for a gas turbine combustor, which overcomes the drawbacks of the prior art.
It is an object of this invention to provide an igniter for a gas turbine combustor, which utilizes improved sealing mechanism from xe2x80x9cO-ringsxe2x80x9d in multiple locations.
It is an object of this invention to provide an igniter for a gas turbine combustor, which has improved durability and function through the use of a hemisphere and spring system.
It is an object of this invention to provide an igniter tip for a gas turbine combustor, which has improved material capability to withstand engine operating conditions. The improved materials will reduce the possible failure mechanisms of the igniter tip.
Accordingly, the present invention comprises an igniter assembly for a combustor of a gas turbine, the combustor being of a type including a case and a liner within said case, the assembly comprising an igniter including an elongate body having a first end, a second end, and a mounting feature intermediate said first and second ends, and the mounting feature includes a semi-hemispherical surface and an electrode extending through the body, and a base having an internal cavity with a first internal land, a second internal land opposite the first internal land, first seal means in sealing contact with the first internal land, and biasing means, such as a spring, in contact with the second internal land and said mounting feature. The mounting feature is located within the cavity, the semi-hemispherical surface is proximate the first seal means, and the biasing means urges the semi-hemispherical surface into sealing contact with the first seal means to prevent the leakage of air therethrough.